Inefficient Regular Expression Complexity Affecting ruby-addressable package, versions <2.5.2-1ubuntu0.1~esm1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-UBUNTU1804-RUBYADDRESSABLE-15982826
- published8 Jul 2026
- disclosed7 Apr 2026
Introduced: 7 Apr 2026
CVE-2026-35611 (opens in a new tab)How to fix?
Upgrade Ubuntu:18.04 ruby-addressable to version 2.5.2-1ubuntu0.1~esm1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream ruby-addressable package and not the ruby-addressable package as distributed by Ubuntu.
See How to fix? for Ubuntu:18.04 relevant fixed versions and status.
Addressable is an alternative implementation to the URI implementation that is part of Ruby's standard library. From 2.3.0 to before 2.9.0, within the URI template implementation in Addressable, two classes of URI template generate regular expressions vulnerable to catastrophic backtracking. Templates using the * (explode) modifier with any expansion operator (e.g., {foo*}, {+var*}, {#var*}, {/var*}, {.var*}, {;var*}, {?var*}, {&var*}) generate patterns with nested unbounded quantifiers that are O(2^n) when matched against a maliciously crafted URI. Templates using multiple variables with the + or # operators (e.g., {+v1,v2,v3}) generate patterns with O(n^k) complexity due to the comma separator being within the matched character class, causing ambiguous backtracking across k variables. When matched against a maliciously crafted URI, this can result in catastrophic backtracking and uncontrolled resource consumption, leading to denial of service. This vulnerability is fixed in 2.9.0.